Lightweight Bike Stem using metal AM
As part of the SAVING Project, 3T RPD worked with Smart Aero Technology, a research and design group specialising in cycling aerodynamics, to develop a bike stem suitable for manufacture using their metal Additive Manufacturing (AM) process. Unhappy with current designs on the market, the aim was to use AM technology to produce an aerodynamically superior part that was lightweight yet still retaining its strength.
After several consultations, 3T concluded that by using an internal lattice structure inside a streamlined external geometry, the project goals could be achieved. The lattice structure provided both strength in the final product and, crucially, support for the outer skin of the part as it’s being built.
Project partners Simpleware’s lattice generation software created a vast number of shape and size combinations by adjusting parameters that control the lattice’s geometry. Titanium was selected as the metal AM build material because of its high strength to weight ratio, and Finite Element Analysis (FEA) was used to determine the best shape, size and density of the lattice based on the external envelope, physical loads and constraints.
The part’s structural integrity was determined by the internal lattice and not solely by the external shape. This meant that both the aerodynamics and strength of the product could be developed independently and without conflict. In addition, the scalability of the technology allows the potential for parts of similar shape, but different size to be built at little extra development cost.
Development of this product is ongoing and has passed through various phases; initially plastic AM parts were manufactured in Nylon to evaluate the design’s form and fit. The Project is currently building and testing the metal AM parts built directly in Titanium.
The SAVING Project is a consortium of seven organisations committed to additive manufacturing. The Project’s objective is to “make more with less – creating sustainable products through innovative design and additive manufacturing”. SAVING stands for: Sustainable product development via design optimisation and Additive manufacturing.
This means the Project will help the UK rapidly exploit additive manufacturing technologies in the areas of lightweight and sustainable products, benefiting the UK’s aerospace and medical sectors.
The Project partners represent every step in the supply chain for AM technology. The partners are Simpleware, Delcam, Exeter University, 3T RPD, Crucible Industrial Design, EOS Electro Optical Systems Ltd and Plunkett Associates Ltd. The Project is funded by the Government’s Technology Strategy Board (TP14/BA036D).